Highly Sensitive Planar Anapole Microresonators for Electron Paramagnetic Resonance Spectroscopy of Submicroliter/Submicromolar Samples

翻译后摘要：电子顺磁共振（EPR）光谱可以提供有关的信息 生理相关条件下生物大分子的结构和动力学。其固有的高 对于某些质量有限的样品，例如膜蛋白，灵敏度仍然不够， 是出了名的难以表达、提纯和结晶。该项目旨在减少 检测为室温下的感应式EPR检测，使产率低 生物大分子样品可以在生理学相关条件下进行研究。实现这一 目的，我们将使用一种新颖的谐振器设计，桥接平面微谐振器之间的差距， 传统的空腔谐振器。我们的新型平面反Anapole微谐振器设计提供了 纳升的有效体积与高品质因数相结合， 在室温下灵敏度的数量级。我们的首要目标是设计和制造 用于在9 GHz和34 GHz下操作的微谐振器。首先，我们将进行有限元模拟， 耦合到波导的谐振器的场分布和反射系数。基于这些 结果，我们将优化设备的几何形状和尺寸，以获得纳升磁场热点 高质量的因素。我们将在NIST纳米工厂制造这些优化的谐振器 设施。接下来，我们将对微谐振器进行表征，并将其集成到商用9 GHz和 自制34 GHz EPR谱仪。我们的第二个目标是证明这些谐振器的可行性 用于结构生物学EPR光谱实验。为了做到这一点，我们将首先设计和制造 能够将纳升样品体积定位在磁热点体积中的微流体装置， 微型谐振器为了验证器件的性能，我们将使用浓度系列的自旋标记 缩氨酸最后，为了证明对生物大分子样品的适用性，我们将研究G蛋白 偶联受体黑视蛋白如果成功实施，这种谐振器设计将实现 EPR光谱前所未有的灵敏度，扩大了其适用于低产量 生物大分子样品，其结构目前知之甚少。

Abstract: Electron paramagnetic resonance (EPR) spectroscopy can provide information about the structure and dynamics of biomacromolecules in physiologically relevant conditions. Its inherently high sensitivity is still inadequate for some mass-limited samples -- for example, membrane proteins -- which are notoriously difficult to express, purify, and crystallize. This project aims to decrease the limit of detection for inductive-detection EPR spectroscopy at room temperature, so that low-yield biomacromolecular samples can be studied under physiologically relevant conditions. To achieve this objective, we will use a novel resonator design that bridges the gap between planar microresonators and conventional cavity resonators. Our novel planar inverse anapole microresonator design provides nanoliter active volumes combined with high quality factors, providing a projected improvement of two orders of magnitude in sensitivity at room temperature. Our first aim is to design and fabricate microresonators for operation at 9 GHz and 34 GHz. First, we will carry out finite element simulations of the field distributions and reflection coefficients for resonators coupled to waveguides. Based on these results, we will optimize the device geometry and dimensions to obtain nanoliter magnetic-field hotspots and high quality-factors. We will fabricate these optimized resonators at the NIST Nanofabrication facility. Next, we will characterize the microresonators and integrate them into a commercial 9 GHz and home-built 34 GHz EPR spectrometer. Our second aim is to demonstrate the viability of these resonators for structural biology EPR spectroscopy experiments. To do this, we will first design and fabricate microfluidic devices capable of localizing nanoliter sample volumes in the magnetic hotspot volume of the microresonator. To validate the device performance, we will use a concentration series of spin-labeled peptides. Finally, to demonstrate applicability to a biomacromolecular sample, we will study the Gprotein coupled receptor melanopsin. If successfully implemented, this resonator design will achieve an unprecedented sensitivity for EPR spectroscopy, broadening its applicability to low-yield biomacromolecular samples whose structures are currently poorly understood.